/**
 * Simple, lightweight, usable local autocomplete library for modern browsers
 * Because there weren鈥檛 enough autocomplete scripts in the world? Because I鈥檓 completely insane and have NIH syndrome? Probably both. :P
 * @author Lea Verou http://leaverou.github.io/awesomplete
 * MIT license
 */

(function() {

    function $(expr, con) {
        if (!expr) return null;
        return typeof expr === "string" ? (con || document).querySelector(expr) : expr;
    }

    function $$(expr, con) {
        return Array.prototype.slice.call((con || document).querySelectorAll(expr));
    }

    $.create = function(tag, o) {
        var element = document.createElement(tag);

        for (var i in o) {
            var val = o[i];

            if (i == "inside") {
                $(val).appendChild(element);
            } else if (i == "around") {
                var ref = $(val);
                ref.parentNode.insertBefore(element, ref);
                element.appendChild(ref);
            } else if (i in element) {
                element[i] = val;
            } else {
                element.setAttribute(i, val);
            }
        }

        return element;
    };

    $.bind = function(element, o) {
        if (element) {
            for (var event in o) {
                var callback = o[event];

                event.split(/\s+/).forEach(function(event) {
                    element.addEventListener(event, callback);
                });
            }
        }
    };

    $.fire = function(target, type, properties) {
        var evt = document.createEvent("HTMLEvents");

        evt.initEvent(type, true, true);

        for (var j in properties) {
            evt[j] = properties[j];
        }

        target.dispatchEvent(evt);
    };

    var _ = self.Awesomplete = function(input, o) {
        var me = this;

        // Setup environment
        o = o || {};

        this.input = input;
        input.setAttribute("aria-autocomplete", "list");

        this.minChars = +input.getAttribute("data-minchars") || o.minChars || 1;
        this.maxItems = +input.getAttribute("data-maxitems") || o.maxItems || 10;

        if (input.hasAttribute("list")) {
            this.list = "#" + input.getAttribute("list");
            input.removeAttribute("list");
        } else {
            this.list = input.getAttribute("data-list") || o.list || [];
        }

        this.filter = o.filter || _.FILTER_CONTAINS;
        this.sort = o.sort || _.SORT_BYLENGTH;

        this.autoFirst = input.hasAttribute("data-autofirst") || o.autoFirst || false;

        this.item = o.item || function(text, input) {
            return $.create("li", {
                innerHTML: text.replace(RegExp(regEscape(input.trim()), "gi"), "<mark>$&</mark>"),
                "aria-selected": "false"
            });
        };

        this.index = -1;

        this.container = $.create("div", {
            className: "awesomplete",
            around: input
        });

        this.ul = $.create("ul", {
            hidden: "",
            inside: this.container
        });

        // Bind events

        $.bind(this.input, {
            "input": me.evaluate.bind(me),
            "blur": me.close.bind(me),
            "keydown": function(evt) {
                var c = evt.keyCode;

                if (c == 13 && me.index > -1) { // Enter
                    evt.preventDefault();
                    me.select();
                } else if (c == 27) { // Esc
                    me.close();
                } else if (c == 38 || c == 40) { // Down/Up arrow
                    evt.preventDefault();
                    me[c == 38 ? "previous" : "next"]();
                }
            }
        });

        $.bind(this.input.form, { "submit": me.close.bind(me) });

        $.bind(this.ul, {
            "mousedown": function(evt) {
                var li = evt.target;

                if (li != this) {

                    while (li && !/li/i.test(li.nodeName)) {
                        li = li.parentNode;
                    }

                    if (li) {
                        me.select(li);
                    }
                }
            }
        });
    };

    _.prototype = {
        set list(list) {
            if (Array.isArray(list)) {
                this._list = list;
            } else {
                if (typeof list == "string" && list.indexOf(",") > -1) {
                    this._list = list.split(/\s*,\s*/);
                } else {
                    list = $(list);

                    if (list && list.children) {
                        this._list = [].slice.apply(list.children).map(function(el) {
                            return el.innerHTML.trim();
                        });
                    }
                }
            }
        },

        close: function() {
            this.ul.setAttribute("hidden", "");
            this.index = -1;

            $.fire(this.input, "awesomplete-close");
        },

        open: function() {
            this.ul.removeAttribute("hidden");

            if (this.autoFirst && this.index == -1) {
                this.goto(0);
            }

            $.fire(this.input, "awesomplete-open");
        },

        next: function() {
            var count = this.ul.children.length;

            this.goto(this.index < count - 1 ? this.index + 1 : -1);
        },

        previous: function() {
            var count = this.ul.children.length;

            this.goto(this.index > -1 ? this.index - 1 : count - 1);
        },

        // Should not be used, highlights specific item without any checks!
        goto: function(i) {
            var lis = this.ul.children;

            if (this.index > -1) {
                lis[this.index].setAttribute("aria-selected", "false");
            }

            this.index = i;

            if (i > -1 && lis.length > 0) {
                lis[i].setAttribute("aria-selected", "true");
            }
        },

        select: function(selected) {
            selected = selected || this.ul.children[this.index];

            if (selected) {
                var prevented;

                $.fire(this.input, "awesomplete-select", {
                    text: selected.textContent,
                    preventDefault: function() {
                        prevented = true;
                    }
                });

                if (!prevented) {
                    this.input.value = selected.textContent;
                    this.close();
                    $.fire(this.input, "awesomplete-selectcomplete");
                }
            }
        },

        evaluate: function() {
            var me = this;
            var value = this.input.value;

            if (value.length >= this.minChars && this._list.length > 0) {
                this.index = -1;
                // Populate list with options that match
                this.ul.innerHTML = "";

                this._list.filter(function(item) {
                    return me.filter(item, value);
                })
                    .sort(this.sort)
                    .every(function(text, i) {
                        me.ul.appendChild(me.item(text, value));

                        return i < me.maxItems - 1;
                    });

                this.open();
            } else {
                this.close();
            }
        }
    };

    _.FILTER_CONTAINS = function(text, input) {
        return RegExp(regEscape(input.trim()), "i").test(text);
    };

    _.FILTER_STARTSWITH = function(text, input) {
        return RegExp("^" + regEscape(input.trim()), "i").test(text);
    };

    _.SORT_BYLENGTH = function(a, b) {
        if (a.length != b.length) {
            return a.length - b.length;
        }

        return a < b ? -1 : 1;
    };

    function regEscape(s) {
        return s.replace(/[-\\^$*+?.()|[\]{}]/g, "\\$&"); }

    function init() {
        $$("input.awesomplete").forEach(function(input) {
            new Awesomplete(input);
        });
    }

    // DOM already loaded?
    if (document.readyState !== "loading") {
        init();
    } else {
        // Wait for it
        document.addEventListener("DOMContentLoaded", init);
    }

    _.$ = $;
    _.$$ = $$;

})();